The problem of stirring and dosing paints, as described in U.S. Pat. No. 3,041,052, FR 2 555 141 or FR 2 536 044, has been previously considered. These patents disclose complex solutions of accurate dosating kinematics by the displacement of a plane shutter sliding on the spout vented by a cap in the section diametrically opposite to the spout, according to the pressure equilibrating principles designed to facilitate a surgeless liquid flow. In addition, any connecting systems between the stirring lid and the cylindrical paint cans are constituted with shafts mountable under the inner edge of a flange. These lids cannot be handled in a very ergonomic way and are reserved for the professional family specializing in body work as accurate dosating units. Furthermore, the use of a plane shutter presents a high risk of a possible trapped finger in the pouring spout area, on which a shutter may act as a guillotine with a very highly automated elastic force eventually leading to injuries of children caused by pressure or cutting action. Additionally, there are stirring lids intended for cans stocked in specific housing units. Each housing unit has its own motoring organs, inside a stirring table, designed to secure homogenization necessary to maintain good usable condition of paint at any time as described in patent EP 1 488 847. This very cumbersome stocking and stirring method is totally inappropriate for use in a domestic environment.
Moreover, environmental-friendly water-based paints became more popular in the year 2006, but their use is more complex, and they require additional user precautions. In particular, sedimentation occurs more quickly when paint comes in contact with air.
To partially thwart these problems and reduce the costs of stirring lids, numerous solutions of lids without cams appeared in the automobile industry, as disclosed in patents EP 0 511 041, U.S. Pat. No. 5,622,289, EP 1 153 844 or FR 2 836 204. Any of these stirring and dosing lids for paints have been developed towards mounting means external to the paint can without modifying the complexity of dosing method by plane shutter translation actuation or rocking kinematic means with inherent risks thereof. Additionally, venting through an air hole is generally existent.
More recently, the patent EP 1 510 363 describes a stirring and dosing lid for automobile body workers including a new swift fixation device to be mounted on the external edge of a typical paint can. This means of attachment comprising several elastic strips offers the advantage of allowing a greater diversity of can diameters to be accommodated, particularly in the automobile industry, while maintaining the very high efficiency of perpetual contact. It is effectively based on a blocking principle with a fish bone effect, as a harpoon which, once in place, will not allow the disengagement of the lid from the can, even if significant strength is applied in an attempt to remove it. On the contrary, the greater the effort of an attempt to extract the lid, the more difficult these attempts become. Thus the only way to withdraw the lid from the paint can is to manually activate the strip, in an opposite direction to the permanent elastic stress pressing it to the external surface of the can, in order to disengage it from the relatively weak outer edge. In fact, a tapered elastic joint shrewdly used in combination then facilitates the lid ejection effortlessly. Moreover, this elastic joint tends to compensate the variations of inner diameters of can flanges and lid deformations by better matching the inner edge of the flange and thus ensuring a good seal as it remains in contact with it, according to lift clearance principles. If these fixation means allow a more ergonomic usage in the lid positioning and release, they do not ensure in return a safety implementation necessary for a paint container resealed in a domestic environment, due to the possible presence of children, thus requiring an additional locking system designed to avoid opening too easily or ensuring adequate protection to prevent its accessibility.
Patent EP 0 515 032 clearly discloses the evolution of lids used for water-based paints in plastic containers which do not require further stirring and having a rocking plug. This system results in being inconvenient and not leak-free when in use. The dosing measurement can become inaccurate due to the rapid clogging of the pouring spout.
Patent EP 1 552 963, consists of a combination of traditional kinematics mounted on a base and to be screwed onto a bottle-shaped container. In this case, the efficiency of a dosing system comprising a sliding plug is universally recognized. But, this new kind of plug only functions as a dosing device and is developed with very cumbersome kinematics and a venting cap from lids commonly used in the automobile industry.
Moreover, patents CA 2 083 901, U.S. Pat. No. 6,419,385 or U.S. Pat. No. 5,199,788 reveal very rustic examples of lids conveniently used for large gallon-type containers. These stirring lids for paints are constituted of a disc adjustable to the different annular edges of a can. A leak-free state is obtained only by screwing the lid on the paint can. Moreover, the lid includes a large sized pouring spout equipped with a plug securely fixed thereon, then a stirring blade jointly coupled with a crank. Though such lids are very simple, they present numerous disadvantages for preserving and securing such devices in a domestic environment. In fact, the lid fixation system on the can offers no security, to the extent that in case of the paint can falling, the lid can be released from its fixation. Thus, the problem of container closure is no longer of regulatory efficiency for paints and does not meet the required standards.
Liquid paints, when sold in cylindrical cans, are generally covered with a disc fixed to the can, either by using strips folded down on the peripheral outer edge, sealing between the can and this disc being provided by a gasket compressed between the disc and the peripheral outer edge of the can, or by a disc compressed on the peripheral inner edge of the can flange, or directly on the can, sealing between the can and this disc being provided by a rigid fixture all around the inner flange or directly around the can circumference.
Once the disc is released, generally it is no longer possible to close the can again to the degree of the original seal, and paint, if not deployed rapidly, will be unusable, generally because the most volatile components evaporate or otherwise solidify. As it is necessary to completely remove the original disc in order to use the paint, this irremediably leads to its irreversible degradation within a short period of time, prejudicial to preservation for extended usage. Once such a can is open, it is not always easy to use the paint. Thus, if the paint needs to be poured into a more appropriate container, i.e. for applying paint with rollers, the paint has a tendency to run over the edge of the can, and forms a crust thereon.
Frequently opening and closing the original disc rapidly deteriorates the contact function with the can and sealing is no longer secured in static storage. Thus, storing paint for a sufficient period from a few hours to a few weeks, allowing the users to be able to work at their own pace from one weekend to the next one, is practically impossible. The infrequent user must buy a plurality of small amounts of paint, which is relatively expensive, or apply paint coats as rapidly as possible upon the can's opening. This situation is as critical as the volume of paint is important.
If the paint needs to be stored for a certain period of time, it should be mixed on a regular basis in order to maintain its homogeneity or to avoid its solidification when exposed to air. But, the degradation of paint by over-oxygenation from a rapid stirring action should be avoided. Therefore, the stirring cabinets for paint cans available for professionals are completely ineffective for individual users in one part because of the rotation speeds greater than 60 rpm of these machines and, secondarily, due to the intensive usage of gun-sprayed paints inducing a high rate of dye renewal. In the sector of decorative paints intended for personal use, the usage frequency rate is not only lower and less sustained, but also usually slower as the application is almost exclusively manual and consumption speed lessens.